ML18033A165

Revises Description of Program for Seismic Qualification of CRD Insert & Withdrawal Piping,Per Rj Clark 860731 Ltr to SA White.Util Requests Review of Program & Issuance of Written Statement Documenting Acceptability of Program

ML18033A165
Person / Time
Site:	Browns Ferry
Issue date:	03/17/1988
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
TAC-00319, TAC-319, TAC-R00319, TAC-R319, NUDOCS 8803220185
Download: ML18033A165 (9)

Text

"ItCCELERLTED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:8803220185 DOC.DATE: 88/03/17 NOTARIZED:

NO FACIL:58-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee AUTH.NAME AUTHOR AFFILIATION GRIDLEY,R.

Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Revises plant seismic qualification of control rod drive insert 6 withdrawal piping description.

DISTRIBUTION CODE: D030D COPIES RECEIVED:LTR ENCL SIZE:>>TITLE: TVA Facilities

-Routine Correspondence NOTES:G.Zech 3 cy.1 cy.ea to: Ebneter,Axelrad,S.Richardson, B.D.Liaw,K.Barr, OI.DOCKET g 05000260 05000260~8 RECIPIENT ID CODE/NAME JAMERSON,C MORAN,D COPIES LTTR ENCL 1 1'1 RECIPIENT ID CODE/NAME PD GEARS,G COPIES LTTR ENCL 1 1 1 1 j A INTERNAL: ACRS Ee EG FIL EXTERNAL: LPDR NSIC NOTES 01 1 1 1 1 1 1 1 1 1 1 9 9 ADM/LFMB OGC 15-B-18 NRC PDR 1 0 1 0 1 1 8 TOTAL NUMBER OF COPIES REQUIRED: LTTR 21 ENCL 19 TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 5N 1 57B Lookout Place MAR I 7 1888 U~S~Nuclear.Regulatory Commission ATTN: Document Control Desk Washington, D.C.20555 Gentlemen:

In the Matter of Tennessee Valley Authority Docket No.50-260 BROWNS FERRY NUCLEAR PLANT (BFN)-SEISMIC QUALIFICATION OF CONTROL ROD DRIVE INSERT AND WITHDRAWAL PIPING This letter revi ses the description of the BFN program for the seismic qual if i cati on of the control rod drive (CRD)insert and withdrawal piping.Thi s'ateri al was requested by 1 etter from R.J.Clark to S.A.Whi te dated July 31, 1986.This letter supersedes the information provided by letters from R~Gri dl ey dated April 8, 1987, and section III.3.6 of revision 1 to the BFN Performance Plan which was transmitted by letter from S.A.White dated July 1, 1 987~Enclosure 1 to this letter describes the BFN program for resolving this i ssue.Enclosure 2 provides the BFN interim operabi 1 i ty cri teri a for Class I seismic piping.TVA requests your review of this program and the issuance of a written statement documenting the acceptability of the program.Please refer any questions regarding this submittal to M.J.May, Manager, BFN Site Licensing, (205)729-3570.Very truly yours, TENNESSEE VALLEY AUTHORITY Enclosures cc: See page 2 R.Grid ey, Direct r Nuclear Licensing and Regulatory Affairs 8803220 1, S5 S803 1 7 PDR ADGCK 05000260 P DCD L>An Equal Opportunity Ernplay<<

l

, U.S.Nuclear Regulatory Commission N!R 17 1888 t cc (Enclosures):

Mr.K.P.Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S.Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr.G.G.Zech, Assistant Director for Projects TVA Projects Division U.S.Nuclear Regulatory Commission One White Flint, North 11555 Rockvi lie Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12, P.O.Box 637 Athens, Alabama 35611 C

ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)SEISMIC QUALIFICATION OF CONTROL ROD DRIVE INSERT AND WITHDRAWAL PIPING This report provides TVA's plan to qualify the control rod drive (CRD)insert and withdrawal piping to Seismic Class I.Issue Adequate-documentation cannot be located to support the seismic qualification of the CRD insert and withdrawal piping.TVA has committed in volume 3 of the Nuclear Performance Plan to analyze and qualify this piping.~Back round In 1973, TVA recognized that the BFN CRD system designer, Reactor Controls, Inc., had not performed an explicit seismic analysis of the insert and withdrawal lines.In accordance with the requirement of 10 CFR 50.55(e), this design deficiency was reported to the AEC-DRO Region II in March of that year.TVA modified some of the insert and withdrawal line supports with the intention of complying with a design criteria for seismically supporting field routed piping two inches in diameter and smaller.(That criteria later became BFN-50-712.)

BFN was licensed for operation on that basis.In September 1985, TVA's engineering staff questioned the seismic adequacy of existing CRD insert and withdrawal pi)ing supports while designing a modification to one of the CRD supports.A field investigation revealed that the typical structural frame supports for the CRD piping bundles were flexible in the horizontal direction perpendicular to the pipe axes which made their ability to resist seismic loads without overstress or excessive deflection questionable.

Adequate seismic design documentation could not be retrieved.

Therefore, TVA contracted with Impell to perform an as-built analysis of the CRD insert and withdrawal piping.This analysis was submitted for the NRC staff's review by TVA's April 8, 1987 transmittal which also requested a change in the design basis for the CRD system.This change was an increase in the level of damping assigned to the CRD piping from 0.5 percent (Operation Basis Earthquake) and one percent (Design Basis Earthquake) to five percent (Design Basis Earthquake).

The modifications to the supports and support frames which resulted from this analysis are essentially complete.Resolution As discussed with your staff in the February 29, 1988 TVA/NRC meeting, TVA is withdrawing the April 8, 1987 request for a change to the CRD's design basis.TVA wi 11 reanalyze the CRD insert and withdrawal piping and evaluate the results to the design criteria.The design criteria used for the CRD piping and supports satisfies the BFN Final Safety Analysis Report (FSAR), Appendix C commitments for piping and pipe support design.Those piping and supports which do not meet the design criteria, but are within the interim operability criteria, will be modified to the design criteria before restart from the next refueling outage (cycle 6).Those which do not meet the interim operability criteria will be modified to the design criteria before restart.A comparison of design and operability criteria is summarized in table l.Licensin Issue Issue: This program invol'ves the use of interim operability criteria for CRD insert and withdrawal piping and supports.Justification:

This criteria (CEB-CI 21.97)assures.structural integrity of the piping and supports and has been proposed for use in the small bore piping program and the program to resolve IE Bulletins 79-02 and 79-14.This criteria is similar to that approved for the Sequoyah Nuclear Plant for large bore supports.Approval of the Sequoyah operability criteria is documented in NUREG 1232.Conclusion The CRD seismic qualification program is comprehensive and provides adequate assurance that the piping and supports will be in conformance with the systems'riginal design basis.Operation of BFN unit 2 for one fuel cycle based upon the interim operability criteria is acceptable.

The CRD system is being extensively upgraded during this outage and the proposed operability criteria is similar to Sequoyah's large bore pi)ing operability criteria which has been accepted by the NRC's staff as documented in NUREG 1232.All modifications required to meet the design criteria will be implemented before restart from the next refueling outage (cycle 6).

1 ENCLOSURE 1 TABLE 1 BROHNS FERRY UNIT 2 CONTROL ROD DRIVE INSERT AND HITHDRAHAL PIPING CRITERIA COMPARISON CHART COMPONENT~Pi in Primary Primary&Secondary DESIGN CRITERIA 1.2SH S*+Sg INTERIM OPERABILITY CRITERIA 2Sy ASME EQ ll or Augmented Fatigue Evaluation J':-:::~=-"-.Concrete...Expansion Anchors Factor of Safety Hedge and Shell Hedge Type 4 Shell Type 5 for Tension 4 for Shear All Types.2 Pipe Support Tensile and Flexural Stress 1.5 X AISC Maximum Limit 0.9S, Lesser of 0.7S<or 1.2Sy Compressive Stress 1.5 X AISC Maximum Limit 0.9S, Maximum Limit 0.9P<R Allowable Shear Stress Maximum Limit 0.52Sy Lesser of 0.42Su 0.72Sy Stress Bolt 0.56Su Greater of 0.7Su or Sy (Minimum)